Process and apparatus for the fluidising and simultaneous cooling of fluidised bed material in a fluidised bed furnace

Process for the fluidising of fluidised bed material in a fluidised bed furnace and simultaneous cooling of the fluidised bed material to be withdrawn from the fluidised bed furnace, in which the combustion air for the fluidised bed furnace is introduced, in at least two superposed planes situated below the fluidised and fired fluidised bed, into the furnace space filled with fluidised bed material. The combustion air introduced into the uppermost plane serves as the fluidising medium for the fluidised bed, and the combustion air introduced into the lower planes serves as the cooling medium for the fluidised bed material which is to be withdrawn, which flows in countercurrent to this, and which is separated from the fluidised bed by the uppermost plane, and is set such that a fixed bed is formed in the region below the uppermost plane. In fluidised bed furnace plants with preheating of the combustion air, combustion air which is not preheated is delivered to at least the lowest plane. Also, apparatus for carrying out the process.